Feasibility Verification Of LTP Protocol Based On Network Coding Under DTN Network Experiment Platform

As one kind of computer network structure, the Delay/Disruption Tolerant Network(DTN) aims to resolve the problem of continuous network connection lacking in the intermittent heterogeneous network, which is running on a mobile scenario, extreme terrestrial environment or the interplanetary network. In the DTN protocol architecture, the LTP protocol is a kind of retransmission protocol by using the automatic retransmission mechanism(ARQ) to ensure the reliability and efficiency of data transmission. For a large-delay deep space communication network, too much retransmission will degrades the data transmission efficiency greatly, while the network coding technique can decrease the number of retransmitted data and thus improve the transmission performance, reduce the consumption of link resource as well as the transmission delay.In this thesis, a modified LTP protocol which combines the network coding and the normal LTP is proposed to improve the performance of LTP protocol. To be specific, the research mainly revolves the following aspects:Firstly, we study the DTN protocol system, especially the LTP protocol systematically. Furthermore, we mainly focus on the software realization and the data processing procedure of the LTP protocol in the ION network. All these work has laid the essential foundation for the designing and improvement of the traditional LTP protocol.Secondly, a modified LTP protocol which combines the network coding and the traditional LTP protocol named the NC-LTP protocol, was proposed. We designed the working principle and procedure in detail. At last, the feasibility of the NC-LTP agreement was verified by some experiments obtained on the simulation platform of the DTN network.Finally, a series of plans were designed to test the proposed NC-LTP protocol based on the simulation platform of DTN network. After the analyzing of the numeral experiment data, we can easily draw the following conclusions:1) The NC-LTP protocol was feasible;2) For the NC-LTP transmitter, the larger packet loss rate, the more data segment;the greater code number, the less data segment. For the NC-LTP receiver, the larger packet loss rate, the more the recovery data segment; the less code number, the more the recovery of data segment3)Under large packet loss rate(p=0.1~0.2), the performance of the NC-LTP protocol is proved superior than that of traditional un-encoded LTP protocol, implying that it is suitable for the large packet loss rate scenario such as the deep space communications.